Image input apparatus for displaying a positionable cursor mark on a reproduced image

Abstract

An image input apparatus has a video camera which photographs an object placed on a stage of the apparatus and which outputs a video signal for reproducing an image of the object on a screen of an external device, such as a monitor. The operator can designate a selected part of the reproduced image by displaying an arrow mark on the image. Display position of the arrow mark is designated by operating cursor keys of a control panel of the image input apparatus while referring to the monitor. The display position is entered in the form of a pair of coordinate values of X-Y coordinates which are defined on the screen. In accordance with the coordinate values, data for displaying the arrow mark as a dot pattern is read from a memory in synchronism with the video signal and mixed with the video signal.

What is claimed is: 
     
       1. An image input apparatus which images an object to display means for reproducing an image of the object on a screen, the image input apparatus comprising: shifting means for shifting a mark on said screen in a two-dimensional direction to designate a display position of said mark on said screen;   determining means for determining a pair of coordinate values Px and Py of corresponding X-Y coordinates of said mark on the screen in accordance with output signals of said shifting means;   first generator means for generating a first saw tooth wave signal in synchronism with a horizontal synchronizing signal of the video signal;   second generator means for generating a second saw tooth wave signal in synchronism with a vertical synchronizing signal of the video signal;   first comparator means for outputting a first coincidence signal when said first saw tooth wave signal coincides with a first voltage level which corresponds to said coordinate value Px;   second comparator means for outputting a second coincidence signal when said second saw tooth wave signal coincides with a second voltage level which corresponds to said coordinate value Py;   X-counter means for counting clock pulses of a predetermined frequency after said first coincidence signal is outputted to generate an X-address signal;   Y-counter means for counting said horizontal synchronizing signal after said second coincidence signal is outputted to generate a Y-address signal;   memory means having a plurality of memory cells, each for storing dot data of a respective dot of a dot pattern which represents said mark;   reading means for reading said dot data from said memory cells by sequentially designating a respective one of said memory cells to be read in accordance with said X-address signal and said Y-address signal to generate a secondary video signal; and   mixing means for mixing said secondary video signal with said video signal to display said mark at said designated display position together with the image on said screen.   
     
     
       2. The image input apparatus of claim 1, wherein the imaging means comprises a CCD image sensor. 
     
     
       3. The image input apparatus of claim 1, wherein the display means comprises cathode ray tube display means. 
     
     
       4. The image input apparatus of claim 1, wherein a pair of said coordinate values Px and Py represents a display position of a predetermined one of said dots of said dot pattern and said dot data of said predetermined dot is stored in one of said memory cells which is predetermined to be read first. 
     
     
       5. The image input apparatus of claim 4, wherein said secondary video signal has a voltage level corresponding to a predetermined brightness level of a dot of said dot pattern on the screen. 
     
     
       6. The image input apparatus of claim 1, wherein the object comprises a sheet of original document. 
     
     
       7. The image input apparatus of claim 6, wherein said mark is an arrow. 
     
     
       8. A method of imaging an object placed on a stage using imaging means to output a video signal to display means for reproducing an image of the object on a screen, the method of imaging comprising the steps of: shifting a mark on said screen in a two-dimensional direction to designate a position of said mark on said screen;   determining a pair of coordinate values Px and Py of corresponding X-Y coordinates of said mark on said screen in accordance with said step of shifting;   generating a first saw tooth wave signal in synchronism with a horizontal synchronizing signal of said video signal;   generating a second saw tooth wave signal in synchronism with a vertical synchronizing signal of said video signal;   outputting a first coincidence signal when said first saw tooth wave signal coincides with a first voltage level which corresponds to said coordinate value Px;   outputting a second coincidence signal when said second saw tooth wave signal coincides with a second voltage level which corresponds to said coordinate value Py;   counting clock pulses of a predetermined frequency after said first coincidence signal is outputted to generate an X-address signal;   counting said horizontal synchronizing signal after said second coincidence signal is outputted to generate a Y-address signal;   storing, in each of a plurality of memory cells, dot data of a respective dot of a dot pattern representing said mark;   reading said dot data from said memory cells by sequentially designating a respective one of said memory cells to be read in accordance with said X-address signal and said Y-address signal to generate a secondary video signal; and   mixing said secondary video signal with said video signal to display said mark at said designated display position together with the image on said screen.